Ejector for punch press



July 1, 1969 P. F. SCHMELTZER ETAL 3,452,577

EJECTOR FOR PUNCH PRESS Sheet Filed April 26, 1967 INVENTORS PwuLEScbmelZgarm ATTORNEYS July 1 1969 P. F. scHMELfi'zER ETAL EJECTOR FOR PUNCH PRESS Sheet Filed April 26, 1967 INVENTORS PwuESolmze @eram;

William/S. Wagner ATTORNEYS July 1, 1969 P. F; SCHMELTZER ETAL 2,

EJECTOR FOR PUNCH PRESS Filed April- 26, 1967 v \2 a? 1 5 65 Qglc INVENTORS 4 l4 l3 Pawfigsalzmelfigerm Q y IfilhamS.Wqgner ATTORNEYS United States Patent 3,452,577 EJE'CTOR FOR PUNCH PRESS Paul F. Schmeltzer, 1501 Raff Road SW., Canton, Ohio 44710, and William S. Wagner, Navarre, Ohio; said Wagner assignor to said Schmeltzer Filed Apr. 26, 1967, Ser. No. 633,827 Int. Cl. B2111 45/00, 22/02; B26d 7/06 U.S. Cl. 72345 14 Claims ABSTRACT OF THE DISCLOSURE An ejector for punch presses having an ejector arm pivotally mounted upon a stationary portion of the press adjacent the recoprocating punch of the press. A pneumatc cylinder upon the ejector arm normally urges a cam follower upon the ejector arm into contact with a cam upon the reciprocating portion. A detachable ejector finger is provided upon the ejector arm.

BACKGROUND OF THE INVENTION Field 0 the invention- The invention relates to ejectors for ejecting work from punch presses adapted for punching such objects as can ends from sheet steel and the like. Such punch presses operate at high speeds making over 300' strokes per minute. It is, therefore, desirable that the ejector mechanism be of as lightweight as possible and that it be made to operate as easily as possible since it must operate at a considerable speed.

The function of an ejector is to remove a stamped article such as a can end which has been fabricated by a punch press operation from the punch portion of the die. The punch has an internal mechanism which extracts the fabricated or drawn can end from the punch, and the function of the ejector is to rapidly remove the can end from its extracted position by striking the can end on its top edge causing it to be removed at a sufiicient rate of travel to permit a more rapid operation of the press.

If no mechanical means were used to remove the can end from the face of the punch, press speeds would be limited by the force of gravity. Most sheet metals are coated and lubricated to promote drawing of the product. This also retards the force of gravity and makes it necessary that some positive means be used to eject the can ends from the area of the die.

Description of the prior ;art

Punch presses of this type such as have been used prior to the present invention have been equipped with various kinds of ejector mechanism, all of which have been mechanical in nature, operated by cams and springs and the like. Very heavy spring pressure was required so that the necessary pressure was still present at the desired time with the spring extended.

This necessarily resulted in excessive wear upon the cam and cam follower and also caused considerable breakage of springs. With such ejector mechanisms it is also difficult to release the ejector arm for the purpose of making adjustments or repairs.

SUMMARY OF THE INVENTION In general terms, the invention may be briefly described as an ejector mechanism including a pneumatic cylinder carried by a yoke pivoted upon a stationary portion of the press adjacent to the reciprocating punch.

A pivot arm is journalled upon the same pivot shaft, inside of the arms of the cylinder yoke, and a piston is pivotally connected at one end to the pivot arm, the other end of the piston being movable within the cylinder.

A curved ejector bar is detachably connected to the cylinder and an ejector tip is detachably connected to the end of the ejector bar. A cam is mounted upon the head of the punch press so as to be movable therewith, and a cam follower in the form of a roller carried by the ejector mechanism is held in contact with the cam by continuous air pressure in the cylinder.

A pawl clamp is clamped upon the pivot shaft and a pawl is pivotally mounted thereon and engages a recess in the pivot arm to limit upward pivotal movement of the pivot arm and hold the ejector mechanism in operative position. When the pawl is released the entire ejector mechanism may be swung upward and backward upon the pivot to permit easy access to the cam for inspecting, adjusting or repairing the same.

An object of the invention is to provide an ejector of the character referred to operated by a pneumatic cylinder.

Another object of the invention is to provide such an ejector including a pivotally mounted ejector bar, a pneumatic cylinder connected thereto, a cam follower upon the ejector bar and a cam carried by the head of the press.

A further object of the invention is to provide an ejector of this character having few movable parts and capable of operating at capacity press speeds.

It is also an object of the invention to provide an ejector of the character referred to in which the pressure is constant and even and will exert the required force at the point of ejection without exerting undue pressure on the cam at any other point.

Another object of the invention is to provide such an ejector mechanism which will reduce vibration to a mlnlmum.

The above and other objects, apparent from the drawings and following description, may be attained, the above described difiiculties overcome and the advantages and results obtained, by the apparatus, construction, arrangements and combinations, subcombinations and parts which comprise the present invention, a preferred embodiment of which, illustrative of the best mode in which applicants have contemplated applying the principal, being set forth in detail in the following description and illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fregmentary side elevation of a portion of a punch press provided with an ejector mechanism embodying the invention, the punch being shown in the lower or closed position;

FIG. 2 is a side elevation of the ejector mechanism with the pawl released and the ejector bar released and swung to upright position fully exposing the cam assembly for inspection or adjustment;

FIG. 3 is a side elevation with parts broken in section, showing the punch in the raised or open position and ejector bar in operated position. ejecting a can end which has just been kicked out of the punch;

FIG. 4 is a fragmentary top plan view of the end portion of the ejector bar showing the replaceable ejector p;

FIG. 5 is a plan view looking in the direction of the arrows, on the line 5-5, FIG. 3;

FIG. 6 is a section on the line 66, FIG. 5;

FIG. 7 is a section on the line 7-7, FIG. 1 showing the cam and cam follower; and

FIG. 8 is an exploded view of the horizontal and vertical slides, the cam and associated parts.

DESCRIPTION OF THE PREFERRED EMBODIMENT The invention is illustrated as applied to an automatic high speed strip feed press such as made by E. W. Bliss Company especially for the manufacture of can ends. In such machines there are usually at least two reciprocating punches and companion stationary dies located side by side for simultaneously punching can ends from a single strip of sheet metal. It is customary in such punch presses to locate the punches and dies at an angle of about 30 to the horizontal, and in the drawings, particularly FIGS. 1 to 3, they are so shown.

A stationary portion of the press is indicated at 1 having a surface 2 located at substantially 30 to the horizontal. The reciprocating press shaft 3 has a cross head, indicated generally at 4, fixed at its lower end. The punch plate 5 is fixed to the lower end of the head 4 and the stripper ring 6 is connected thereto by the stripper ring nut 7. The punch shell is indicated at 8, the punch back at 9, the knock-out ring at 10, the punch core at 11, and the knockout stem at 12.

It will be understood that the punch as well as the stationary die may be of any conventional construction and in themselves form no part of the present invention which is concerned only with the ejector mechanism.

The die is stationary relative to the punch and comprises the die shoe 13, the cut edge 14, the draw ring 15, the die core ring 16, and the die core 17. For the purpose of locating the ejector mechanism adjacent to the punch and die, mounting brackets are attached to the inclined surface 2 of the press, one of said brackets being indicated generally at 18 in FIGS. 1, 3, 5 and 6.

A pivot shaft 19 is mounted upon the mounting brackets by means of shaft clamps 20, each of which is adjustably mounted upon the corresponding bracket by means of cap screws 21 located through the elongated slots 22.

Each shaft clamp 20 has a split ring clamping portion 23 which receives one end of the pivot shaft 19. A screw 24, located through the cars of the clamping portion 23, clamps the shaft 19 within the split clamping portion 23.

A pawl clamp, indicated generally at 25, is fixed upon an intermediate portion of the pivot shaft 19 by means of cap screws 26 located through the split clamping portion 27 thereof. A pawl 28 is pivotally mounted between the ears 29 of the pawl clamp upon a pin 30, for a purpose to be later explained.

A pivot arm, indicated generally at 31, includes the bifurcations 32 pivotally mounted upon the shaft 19 on opposite sides of the pawl clamp 25. Spaced cars 33 are formed on the end of the pivot arm 31 between which is pivotally mounted the ear 34, on the end of the hollow piston 35, by means of the pin 36. A spaced pair of lugs 37 are formed on the outer side of one of the bifurcations 32 for a purpose to be later described.

The other end of the piston 35 is slidably located within a pneumatic cylinder 38. A pair of slightly diverging arms 39 may be formed integrally with or rigidly attached to the cylinder on opposite sides thereof, each arm being provided with a bearing portion 40. pivotally mounted upon the shaft 19 on opposite sides of the bifurcationss 32 of the pivot arm.

Grease fittings 41 may be provided upon the bearing portions 40 and upon the car 34 of the piston. One of the bearing portions 40 has a lug 42 which is located between the lugs 37 on one of the bifurcations 32 of the pivot arm.

Air under pressure may be admitted to the cylinder 38 by a hose 43 communicating with a port 44 in the lower end of the cylinder. A bracket extension 45 is formed upon the lower end of the cylinder 38 and has an angularly disposed ear 46 formed thereon. A cam follower is mounted upon the ear 46 in the form of a roller 47 journalled upon the pin 48. The cylinder 38, arms 39, extension 45 and ear 46 may be formed as an integral forging or the like.

The upper end of an ejector bar 49 is connected at one end to the top surface of the extension 45 and is curved forwardly and downwardly as at 50 toward the lower end of the punch. As best shown in FIG. 5, the upper end of the ejector bar 49 may be located in a longitudinal groove 51 in the extension 45 and the ejector bar may be adjustably connected to the extension 45 as by the cap screws 52 and slots 53 in the ejector bar.

The free end of the ejector bar 49 has an elongated groove 54 in its upper surface, said groove being open through the adjacent end of the ejector bar and being rounded as at 55 at its inner end. An ejector tip 56, having a rounded inner end 57, fitting the rounded end 55, is located in the groove 54 and attached to the ejector arm 49 by the cap screws 58.

With the exception of the ejector tip 56, which may be formed of tool steel, all of the moving parts of the ejector mechanism may be formed of a suitable aluminum alloy in order to reduce the weight thereof.

As shown in FIG. 3, the lower end of the hollow piston 35 is slidably located within the cylinder 38 and is provided with any suitable form of piston ring, such as the O-ring indicated at 59. The lug 42 on the bearing 40, being located between the spaced lugs 37 on the pivot arm 31, controls the relative movement of the piston 35 and cylinder 38 so that the piston cannot become accidentally displaced from the cylinder.

A cam 60 is mounted upon the cross head 4 of the press for movement therewith and cooperates with the cam follower 47 on the ejector bracket extension 45. This cam may be mounted for horizontal and vertical adjustment upon the cross head.

For the purpose of adjustably mounting the cam upon the cross head, a cam plate 62 is shown attached to the cross head as by cap screws 63. The camp plate has a T-shape groove 64 therein which slidably receives the T-shape nut 65 having a threaded bore 66.

A horizontal slide 67 is slidably adjustably mounted upon the cam plate and has a depending rib 68 slidably received in the upper end of the T-shape groove 64. Flanges 69 are formed on the upper face of the horizontal slide 67 at opposite edges thereof, and an aperture 70 is formed through the horizontal slide at one side of the longitudinal center line thereof.

The vertical slide 71 is longitudinally slidable upon the top face of the horizontal slide 67, between the flanges 69 thereof. A groove 72 is formed in the top face of the vertical slide 71 to receive the lower edge of the cam 60, which is secured upon the vertical slide 71 by the cap screws 73 located through apertures 74 in the vertical slide and screwed into the threaded bores 75 in the cam 60.

An elongated slot 76 is formed in the vertical slide 71, parallel to the groove 74 therein, to receive the reduced lower portion 77 of the T-shape locating block 78. Set screws 79 are located through opposite ends of the vertical slide 71 and into opposite ends of the slot 76 therein for engagement with the locating block 78 to hold it in adjusted position.

An aperture 80 is formed through the locating block 78 to receive the bolt 81, which is located through the aperture 70 of the horizontal slide and receives the nut 65 for holding the vertical and horizontal slides clamped in adjusted position upon the cam plate 62, thus adjustng the cam upon the press head.

OPERATION With all the parts properly adjusted and constant air pressure in the cylinder 38, as the punch reaches the lower or closed position, as shown in FIG. 1, to punch a can end from the sheet metal strip S, the cam follower 47 will be riding on top of the cam 60 so as to hold the ejector bar 49 in the raised position so that the ejector tip 56 is spaced upwardly from the punch and die.

During this time the punch has blanked out a disc from the sheet metal strip S and formed a can end therefrom. As the punch and die start to separate on upward movement of the punch, the can end remains in the punch.

During continued upward movement of the punch, the knock-out ring is operated by usual and .well known mechanism in the press to push the can end, indicated at C, out of the punch and at this time the cam follower 47 has ridden down over the inclined lower end of the cam 60 permitting the ejector bar 49 to be moved to the lowered position as shown in FIG. 3, striking the top edge of the can end C and quickly knocking it down from between the punch and die.

Due to the construction of the ejector mechanism and the light weight thereof as compared with present ejector mechanisms, a press equipped with the same may be operated at maximum speed. The pneumatic pressure in the cylinder is constant and can be regulated to exert the required forceat the point of ejection without exerting undue pressure on the cam at any other point. The pneumatic pressure also reduces vibration as compared to spiral springs, or boxed and slatted cams as a source of power, as in present practice.

The ejector cam is mounted on a cam plate which is keyed in position to the cross head of the press, and the cam plate is slotted to permit horizontal positioning of the cam. Each cam is contained in :a cam bracket to permit individual vertical adjustment. Horizontal and vertical adjustments can be obtained without the cam face becoming out of parallel with the face of the cam fol-lower.

By mounting the cams on the cross head of the press it is possible to mount the cam follower on the ejector |bar extension bracket, thus eliminating the greater portion of weight from the ejector bar and placing the weight on the cross head of the press where weight is of no consequence.

The ejector is simple to adjust and readily accessible. By releasing the air pressure in the cylinder the pawl 28 may be easily pulled out of engagement with the notch 61 in the pivot arm so as to unlatch the ejector bar to swing it into upright position as shown in FIG. 2, fully exposing the can assembly for inspection or adjustment.

The ejector will accommodate all sizes of can ends from 202 to 404 diameter inclusive without modification, merely by changing the inexpensive metal ejector tip 56 to one of desired size.

Since all moving parts are made of aluminum the ejector is of minimum weight. The pneumatic cylinder being horizontal to the cross head of the press is neat in appearance and requires little vertical space, thus eliminating bulky safety guards.

In the foregoing description certain terms have been used for brevity, clearness and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated and described herein are by way of example, and the scope of the present invention is not limited to the exact details of construction.

Having now described the invention or discovery, the construction, the operation, and use of preferred embodiments thereof, and the advantageous new and useful results obtained thereby; the new and useful construction, and reasonable mechanical equivalents thereof obvious to those skilled in the art, are set forth in the appended claims.

We claim:

1. Ejector mechanism for a punch press having a reciprocating head, a punch carried by the head, and a stationary die below and cooperating with the punch, said ejector mechanism comprising a pneumatic cylinder pivotally mounted on a stationary portion of the press, a piston cooperating with the cylinder, pivoted means pivotally connecting the piston to the press, an ejector :bar connected to said cylinder and curved toward the lower end of the punch, a cam mounted upon the reciprocating head of the press, a cam follower connected to said ejector bar and cooperating with said cam, there being fluid pressure between the piston and thecylinder, the resulting force by the. pressureholding the cam follower against the cam and urging the curved end of the ejector bar downwardly beyond the lower end of thepunch.

2. Ejector mechanism as defined in claim 1 in which the cam is mounted for longitudinal and lateral adjustment upon the head of the press. I

3. Ejector mechanism as defined in claim 1 including a pivot arm pivoted upon a stationary portion of the press, the piston having one end slidable within the cylinder and its other end pivotally connected to said pivot arm.

4. Ejector mechanism as defined in claim 1 in which there is a bracket extension upon the cylinder means, an ear upon said bracket extension, and a cam follower roller journalled upon said ear, and in which the ejector bar is detachably connected to said bracket extension.

5. Ejector mechanism as defined in claim 1 including an ejector tip detachably connected to the ejector bar.

6. Ejector mechanism as defined in claim 3 including cooperating lugs upon the cylinder means and the pivot arm for limiting relative movement between the cylinder and piston.

7. Ejector mechanism as defined in claim 3 including a pivot shaft mounted upon a stationary portion of the press, said cylinder means and said pivot arm being pivoted upon said shaft.

8. Ejector mechanism as defined in claim 7 including a clamp upon the pivot shaft, the pivot arm having bifurcations located on opposite sides of said clamp, and the cylinder means having yoke arms located on each side of the bifurcations.

9. Ejector mechanism as defined in claim 7 including mounting bracket means upon which the pivot shaft is mounted.

10. Ejector mechanism as defined in claim 2 including a cam plate fixed to the head of the press, a horizontal slide laterally adjustably mounted upon said cam plate, a vertical slide longitudinally adjustably mounted upon the horizontal slide, the cam being fixed to said vertical slide, and screw means holding said horizontal and vertical slides in adjusted position relative to said cam plate.

11. Ejector mechanism as defined in claim 10 in which there is a T-shape laterally disposed groove in the top of the cam plate, a nut slidable in said groove, a depending laterally disposed rib on the underside of said horizontal slide located in said groove, upright flanges at the longitudinal edges of the horizontal slide, there being an aperture in said horizontal slide, the vertical slide being slida'ble between said flanges, a longitudinally disposed slot in the vertical slide, a. T-shape locating block received in said slot and having an aperture therein, and a screw located through the apertures in the locating block and horizontal slide and screwed into said nut.

12. Ejector mechanism for a punch press having a reciprocating head, a punch carried by the head, and a stationary die 'below and cooperating with the punch, said ejector mechanism comprising a pneumatic cylinder pivotally mounted on a stationary portion of the press, an ejector bar connected to said cylinder and curved toward the lower end of the punch, a cam follower connected to said ejector bar and cooperating with said cam, a pivot arm pivoted upon a stationary portion of the press, a piston having one end slidable within the cylinder and its other end pivotally connected to said pivot arm, and a pawl pivoted upon a stationary portion of the press and engaging said pivot arm for normally holding the cam follower in contact with the cam when the cylinder and piston are under air pressure.

13. Ejector mechanism for a punch press having a reciprocating head, a punch carried by the head, and a stationary die below and cooperating with the punch, said ejector mechanism comprising a pivot shaft mounted on a stationary portion of the press, a pneumatic cylinder pivoted upon said shaft, an ejector bar connected to said cylinder and curved toward the lower end of the punch,

a cam mounted upon the reciprocating head of the press, a cam follower connected to said ejector barand cooperating with said cam, a pivot arm pivoted upon said shaft, a piston having one end slidable within the cylinder and its other end pivotally connected to said pivot 'arm, a clamp upon the pivot shaft, the pivot arm having bifurcations located on opposite sides of said clamp, and the cylinder having yoke arms located on each side of the bifurcations, there being a notch in the pivot arm, and t a pawl pivotally mounted upon said clamp and engaging said notch for normally holding the cam follower in contact with the cam when the cylinder and piston are under air pressure.

14. Ejector mechanism for a punch press having a reciprocating head, a punch carried by the head, and a stationary die below and cooperating with the punch, said ejector mechanism comprising a pivot shaft mounted on a stationary portion of the press, a pneumatic cylinder pivoted upon said shaft, an ejector bar connected to said cylinder and curved toward the lower end of the punch, a cam mounted upon the reciprocating head of the press, a pivot arm pivoted upon said shaft, a piston having one end slidable within the cylinder and its other end pivotally connected to said pivot arm, a clamp upon the pivot shaft,

the pivot arm having bifurcations located on opposite sides of said clamp, the cylinder having yoke arms located on each side of the bifurcations, there being a notch in the pivot arm, a pawl pivotally mounted upon said clamp and engaging said notch for normally holding the cam follower in contact with the cam when the cylinder and piston are under air pressure, a bracket extension upon the cylinder, an ear upon said bracket extension, and a cam follower roller journalled upon said ear and cooperating with said cam, the ejector bar lbeing detachably connected to said bracket extension.

References Cited UNITED STATES PATENTS 2,694,994 11/ 1954 Weymouth et al 72427 2,755,759 7/ 1956 Roberts 72427 ANDREW R. JUHASZ, Primary Examiner.

J. F. COAN, Assistant Examiner.

US. Cl. X.R. 

